New insight into the soil bacterial and fungal microbiome after phosphorus biofertilizer application as an important driver of regenerative agriculture including biodiversity loss reversal and soil health restoration

At present, the exploitation of biofertilizers is revealing the vast potential for the advancement of sustainable and organic agriculture and the improvement of arable soil quality. Therefore, we investigated the capacity of an innovative phosphorus biofertilizer to enhance the activity and diversity of the soil microbiome inhabiting chemically degraded soil (type Abruptic Luvisol). The two-year field experiment comprised a control treatment (FC) devoid of microbial enrichment, an optimal dose of fertilizer containing beneficial microorganisms (FA100) and a dose of fertilizer that was 40 % below this optimal level and contained microorganisms (FA60). Phosphorus biofertilizer increased soil enzymatic activity immediately after application and between the corresponding treatments in subsequent sampling times, it alleviated the effects of metabolic stress, improved phytoavailable phosphorus content and increased maize yield. Identification based on the terminal restriction fragments size revealed the presence of microorganisms important for soil health such as phosphorus solubilizers, nitrogen fixers, biological control agents, entomopathogens, mycorrhizal fungi, bioremediators and plant growth promoters. Next Generation Sequencing (NGS) showed that the application of phosphorus biofertilizer changed the relative abundance of different microbial phyla, classes and orders, increased the diversity of soil microorganisms and indicated that the composition of the soil microbiome was also dependent on the sampling time. The prediction of bacterial community function using PICRUSt demonstrated that the application of biofertilizer raised the number of functional sequences associated with metabolism and cell processes, including phosphorus compound pathways. FUNGuild showed that saprotrophic and symbiotrophic fungi were more abundant in microbiologically enriched treatments. Our results proved that the phosphorus biofertilizer used offers a sustainable and promising solution to the problem of reducing traditional mineral fertilizer inputs while ensuring soil microorganism welfare and enhancing land productivity, and, what is more, it can be effectively exploited in regenerative agriculture and as a factor used to enhance resilience to climate change.